Not Applicable.
This invention relates to dippers for large shovels, and particularly to a dipper door and dipper assembly including a door.
Shovel dipper assemblies include a dipper formed with teeth at their leading edge and a flat dipper door. The door closes the dipper open bottom, and holds earth and other load materials that are loaded into the dipper by the action of the shovel. Structural elements, such as sides, and rear walls are disposed beneath the door or overlap the outer surface of the dipper walls to strengthen the door. The volume of the dipper assembly is defined by dipper walls.
The dipper door must be held closed while the dipper is being loaded and while the load in the dipper is swung to a deposit point. At that point, the dipper door must be opened to allow the contents of the dipper to fall out. Conventionally, the locking of the dipper door is accomplished by a mechanical latch which holds the door in a closed position and which is released by a cable to allow the door to swing open under its own weight and the weight of the contents of the dipper. The door is relatched by allowing it to swing closed. An example of such a mechanical latch is found in U.S. Pat. No. 5,815,958 issued Oct. 6, 1998, for xe2x80x9cExcavator Dipper Latch Assembly Having Removable Tapered Latch Barxe2x80x9d.
The dipper door structural elements are required to provide sufficient structural integrity to support the load material in the dipper when the door is closed. The door structural elements increase the weight of the door, and thus the entire weight of the dipper assembly. A need exists to reduce the weight of the dipper assembly without reducing the volume for load material of the assembly.
The present invention reduces the weight of a dipper assembly by providing a dipper door having structural members which define a volume for holding load material. The volume of the dipper door allows the dipper volume to decrease by removing dipper material (such as by shortening the dipper walls) while maintaining the same volume for the dipper assembly. Reducing the dipper volume reduces the weight of the dipper, and thus the assembly.
The dipper assembly includes a dipper having an open bottom and forward end, and a door pivotally linked to the dipper. The dipper bottom is defined by dipper wall bottom edges. The door has a bottom wall and side walls which extend above the bottom wall to define a volume between the side walls, wherein top edges of the side walls abut bottom edges of the dipper wall bottom edges to close the dipper bottom.
In one aspect of the present invention, the door is pivotally mounted to the dipper at a pivot point offset a distance from the open bottom in a direction toward the forward end. The door can include a back wall extending upwardly from a back edge of the bottom wall and joined at each end to the door sidewalls, wherein a top edge of the door back wall abuts one of the dipper wall bottom edges.
The foregoing and other objects and advantages of the invention will appear in the detailed description which follows. In the description, reference is made to the accompanying drawings which illustrate preferred embodiments of the invention.